SIMULTANEOUS MEASUREMENT OF LIGHTNING PARAMETERS FOR STROKES TO THE TORONTO-CANADIAN-NATIONAL-TOWER

Successful simultaneous measurements of significant parameters for lig htning strikes to the Canadian National (CN) Tower in Toronto have bee n performed since the summer of 1991. Three 10-bit 10-ns computer-cont rolled double-channel digitizers, with long segmented memory, have sim ultaneously captured the current derivative at the CN Tower and the co rresponding electric and magnetic fields 2.0 km north of the tower. Li ghtning flashes to the tower were videotaped from two mutually perpend icular directions for the purpose of constructing a three-dimensional image of the lightning path. Furthermore, the return stroke velocity, a parameter also needed for the analysis of lightning radiation models , has been measured by a computer-controlled photodiode system. In thi s paper all relevant parameters for a CN Tower lightning stroke, obser ved on August 17, 1991, are shown and analyzed.